Support of a MIP capable terminal in an IP based UMTS network
Original Publication Date: 2001-Jul-01
Included in the Prior Art Database: 2003-Jul-23
There is a trend, that the UMTS network will migrate to IP based networks (refer to the activities in the 3GPP standardisation for UMTS Release 2000). As a part of this evolution, UMTS specific protocols are being replaced by more generic protocols, that are applied in the Internet and IP world. One such replacement applies to the mobility management. The aim of the mobility management is to track the actual cell where a mobile is roaming in order to route downstream packets (with a fixed IP destination address) to that cell. The IETF has standardised the „mobile IP" protocol to handle the mobility management for any kind of network, independent of the applied access technology (refer to [MIPv4]: RFC2002 IP mobility support and [MIPv6]: IETF Draft mobility support in lpv6 draft-ietf-mobileip-ipv6-12.txt). In this contribution, we provide enhancements to the MIP standard in order to make it work and improve its efficiency when applied in conjunction with a UMTS radio access network. In order to downlink packets, being correctly routed to the actual base station, each time a mobile host moves to another cell. The mobile host must register its actual point of attachment address (COA- „care of address") with one or more mobility agents in the terrestrial network. The registration is performed by sending a „binding update" message towards the mobility agent(s). The mobile host decides when it is necessary to register by means of a mechanism called „move detection". According to the actual [MIPv4] and [MIPv6] standards, move detection is based on broadcasted addresses, that the host receives an the user data channels, either from a „foreign agent" [MIPv4] or the default router servicing the actual base station [MIPv6]. When the mobile host detects a change of the broadcasted address, it starts the registration procedure. In order to speed up the handoff process (important for real time services and to avoid packet loss), the option exists that the MIP client is triggered by the radio part of the mobile host. But even in that case, the mobile host must solicit for advertisements to find out whether a registration is really required (takes some time). Further it is not described what should be the event(s) an the UMTS radio interface to launch the trigger for registration.